1. Field of the Invention
The present invention relates to a cover structure with a vent portion permitting the escape and intake of a fluid such as air, gas, and the like, and more particularly, to a cover structure that is used in a variety of electronic systems such as a plasma display panel (PDP) TV, a liquid crystal display (LCD) projector, and the like, the cover structure being provided with a vent portion that can minimize noise caused by fluid flow forced by a cooling fan.
2. Background of the Prior Art
Generally, electronic display systems such as a PDP TV and a LCD projector generate a large amount of heat in the course of their operations.
For example, the PDP TV generates a large amount of heat by the emission of ultraviolet rays of plasma. Such heat is generally discharged out of the system by, for example, a cooling fan. If the heat is not sufficiently discharged, the system may not be stably operated, and it may even malfunction. Particularly, as the PDP system generates relatively high heat compared to other systems, it requires a large cooling capacity compared to other systems.
In addition, in case of the LCD projector, in order to project an image formed on the LCD on a large-sized screen, a lamp of the LCD projector should be increased in its brightness.
However, when the brightness of the lamp is increased, an internal temperature of an optical engine is also increased, thereby deteriorating the functions of the projector. For example, the liquid crystal may be boiled or the polarizer may be burned.
To solve these problems, a cooling fan is installed in the system to forcedly discharge the heat out of the system.
However, the cooling fan causes noise. The noise can be classified into three types of noise: cooling fan operating noise, a vibration noise caused by a cooling fan support, and fluid flow noise caused by the flow of fluid forced by the cooling fan.
Many designs have been proposed to properly deal with the cooling fan operating noise and the vibration noise, but no design has been proposed for the fluid flow noise.
FIG. 1 shows a conventional cover structure with a cooling fan.
As shown in the drawing, a cover structure comprises a back cover 10 formed on a rear wall of a flat display, as an example, and a cooling fan 20 disposed spaced away from the back cover 10 by a predetermined distance. The back cover 10 is provided with a vent portion 11 through which air comes in or goes out.
At this point, the distance “a” between the cooling fan 20 and the back cover 10 is designed to be as small as possible so as not to deteriorate the slim characteristic of the flat display.
However, since the fluid flow noise is not considered when designing the distance “a”, severe fluid flow noise is generated when the cooling fan 20 operates.